Most sheaths that have been designed for carrying knives are intended to permit the knife to be pulled quickly from the sheath. In some instances, however, the knife sheath is provided with a strap to hold the knife securely in position. In knife and sheath arrangements designed primarily for underwater use the sheath is often provided with a flexible, stretchable, rubber-like loop that extends over the handle to secure it in position
While these means for securing a knife in a sheath are adequate for most purposes, they have limitations especially with a knife worn in unusual environmental situations such as occur when the knife is carried by divers. Divers require a knife and sheath combination in which the knife will remain securely in the sheath during normal movement of the diver but which can be quickly and easily removed and returned by the diver to the sheath when he wishes. While the sheath constructions heretofore in use by divers securely hold the knife in the sheath during normal movement of the diver these constructions do not ordinarily permit easy removal of the knife. The rubber ring commonly used has to be stretched or distended by the diver and since the diver works underwater and frequently in the dark it is not always easy to free the knife from the rubber ring and then remove it from the sheath. Further it is not always easy for the diver to return the knife and secure the loop over the sheath under such adverse conditions.